I am the type of user that uses CGam in order to snap pictures, and then uses native Sailfish apps in order to share them (Telegram Fernschreiber, Facebook through browser, etc.).
The problem was that the SFOS Gallery app would not show pictures from the android_storage/DCIM, although there is a whitelist line in the Pictures.permission file.
I solved this by creating a symlink in the /home/defaultuser/Pictures folder:
Can you please check what gsettings get org.freedesktop.Tracker.Miner.Files index-recursive-directories gives for you? In SFOS 3.x this included /home/nemo/android_storage/DCIM and many other similar folders already, which also causes the Gallery app to show files under this directory.
Pictures.permission is not the same as the tracker path - but your tracker path look fine to me (but I did not yet upgrade to 4.x to check because of the known issues).
my ugly workaround is to share to Nextcloud and download it to Android from Android-Nextcloud app. Which means quite a bit of unnecessary network traffic.